The fire started about 2:10 p.m. when a westbound grain train derailed about a half-mile west of Casselton and slammed into an eastbound 106-car train carrying crude oil. More than 10 oil cars exploded, pumping thick clouds of black smoke into the air.

Fire officials expected the flames to rage overnight in the oil cars that had not been disconnected.

For several hours, the Cass County Sheriff’s Office told the roughly 2,400 residents of Casselton to stay indoors, eventually asking the southwest corner of town to evacuate.

But as the forecast called for shifting winds that could push the billowing smoke east over the city, Sheriff Paul Laney and other officials agreed Monday night to ask the entire town to clear out as a precautionary measure.

“This is nothing to play with,” Laney said, adding that the smoke would be most harmful to those with respiratory illnesses. “We’re going to err on the side of caution.

Central Cass High School in Casselton and Fargo’s Discovery Middle School were opened as shelters. Casselton is about 20 miles west of Fargo.

Koepplin watched the thick smoke billow in the air from her house just three blocks from the site of the crash.

“We heard the boom three times,” she said while sitting on the floor of the Central Cass High School gymnasium. “It shook our windows.”

Though the county stopped short of a mandatory evacuation, Laney stressed the seriousness of their “strong recommendation” that the people of Casselton leave town as crews try to maintain the flames.

“We hope that people will listen,” he said.

Koepplin grabbed a blanket and a pillow, dropped her dogs off at her daughter’s house and headed to the school.

Laney said he’s not sure when they’ll give the all-clear for residents to return. He said county officials will re-assess the situation overnight.

Cause unclear

Black smoke filled the sky within minutes of the collision, casting a long shadow over much of Casselton.

Police immediately urged residents to stay indoors, and blocked off traffic within a mile of the crash. Even air traffic was restricted from getting close to the train.

BNSF spokeswoman Amy McBeth said no injuries were reported in the crash. She didn’t know the oil train’s destination or origin.

Crews managed to detach about half of the oil train’s 106 cars to get them out of harm’s way, Morris said. They will allow the remaining cars to burn out.

“We’ll just have to let it burn off it sounds like, just because of the intensity,” she said Monday night.

The cause of the crash is unclear.

Peter Knudson, a spokesman for the National Transportation Safety Board, said they are assembling a team to investigate the derailment and crash. Most of the team is from Washington, D.C., and the team leader is from Chicago.

The NTSB team is expected to land in North Dakota in the morning. BNSF personnel from across the nation also are en route to help respond.